JP7260848B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to fixing devices and image forming apparatuses.

An electrophotographic image forming apparatus includes a fixing device for fixing a toner image onto a recording medium such as transfer paper. In the fixing device, for example, a nip portion is formed by pressing a pressure member (pressure roller) against a heated fixing member (fixing roller or fixing belt), and the recording medium passes through the nip portion. The carried toner is melted, and the toner image is fixed on the recording medium.

There are many constituent members of the fixing device that need to be replaced periodically as well as in the event of a failure, and the need for maintenance work or part replacement work arises depending on the usage conditions.
The above work is basically performed by service personnel, but the content of the work affects the load on the service personnel and labor costs, which in turn increases the cost burden on the user. For example, see Patent Document 1).

Japanese Patent Laid-Open No. 2002-100000 discloses a method for easily replacing a heating roll and a heater in a heating roll unit and a fixing device of an image forming apparatus, and eliminating variations in the mounting position of the heater with respect to the heating roll in the axial direction of the heating roll. For the purpose of reducing the number of heaters and facilitating attachment and detachment of the heaters when a plurality of heaters are arranged inside the heating roll, a pair of bearings at both ends in the axial direction of the heating roll, and a pair of mounting members respectively mounted on the outer race, the pair of mounting members comprising a first mounting member provided with a heater positioning member for positioning the outer end of the heater in the sliding direction; A heating roll unit has been proposed which includes a second mounting member that supports a positioning elastic pressing member that presses against a member. Moreover, Patent Literature 1 discloses a mode in which a handle portion that can be grasped by an operator is provided.

According to Patent Literature 1, it is possible to improve the workability of replacing a heater in a heating roll unit. However, improvement of workability in maintenance of other units constituting the fixing device and replacement of parts of members constituting the unit is still a big problem.

For example, the pressure roller that constitutes the fixing device has a problem of poor handling due to its size and weight. When a worker grips a grip portion such as a handle to perform an attachment/detachment operation, if the device is accidentally dropped, there is a risk of injury to the worker as well as damage to the pressure roller. Further, since heat-resistant grease is applied to the drive gear provided at the end of the pressure roller, the grease may adhere to the fingers, clothes, etc. of the operator during replacement. If it is difficult for the serviceman to carry out the replacement work at the user's site, the replacement will be performed for each pressure unit including parts that do not originally need to be replaced at the service location, which is disadvantageous in terms of time and cost. I have a problem.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fixing device capable of improving the workability of maintenance and parts replacement for a pressure unit having a pressure roller regardless of the working environment and working conditions.

In order to solve the above-described problems, a fixing device of the present invention includes at least a heating means, a rotatable fixing member, and a pressure roller that contacts the fixing member to form a nip portion. The roller is provided with bracket members at both ends in the direction of the rotation shaft. The bracket members include a rotation shaft portion support surface through which the rotation shaft portion is inserted, and a rotation shaft portion support surface provided above the rotation shaft portion support surface to rotate the rotation shaft portion. and a bearing member supporting surface that faces the outer peripheral surface of the bearing member that can be supported. wherein the rotating shaft portion is inserted through the rotating shaft portion support surface via the bearing member, the bearing member support surface has a knob portion that can be gripped with fingers, and the knob portion is It is characterized in that it is arranged on the upstream side in the conveying direction of the recording medium with respect to the rotating shaft of the pressure roller.

According to the present invention, it is possible to provide a fixing device capable of improving the workability of maintenance and parts replacement for a pressure unit having a pressure roller regardless of the working environment and working conditions.

1 is a schematic configuration diagram showing an example of an image forming apparatus according to the present invention; FIG. 1 is a perspective view schematically showing a state in which a fixing device according to the present invention is mounted in an image forming apparatus; FIG. 1 is a perspective view schematically showing the appearance of a fixing device according to the present invention; FIG. 1 is a perspective view schematically showing a state in which a fixing device according to the present invention is divided into upper and lower units; FIG. 4A and 4B are a perspective view and a side view, respectively, schematically showing bracket members at both ends of the pressure roller; FIG. FIG. 5 is an explanatory diagram showing a mode of a knob portion of the first bracket member; FIG. 11 is an explanatory diagram showing a mode of a knob portion of a second bracket member;

A fixing device and an image forming apparatus according to the present invention will be described below with reference to the drawings. In addition, the present invention is not limited to the embodiments shown below, and can be changed within the scope of those skilled in the art, such as other embodiments, additions, modifications, deletions, etc. is also included in the scope of the present invention as long as the functions and effects of the present invention are exhibited.

An embodiment of an image forming apparatus according to the present invention will be described with reference to FIG.
FIG. 1 is a schematic configuration diagram showing an image forming apparatus, specifically a copier printer capable of forming a monochrome image. It also functions as a printer by connecting to a PC.
Since the image forming apparatus of the present embodiment is a copying machine, it has a document reading unit that functions as a scanner. may be omitted.

The schematic configuration and operation of the image forming apparatus of this embodiment will be described below.
The image forming apparatus 10 has a scanner unit 104 that accommodates an illumination device, an optical system, a CCD image sensor, and the like.
An automatic document reader (hereinafter referred to as "ADF unit" (ADF: Auto Document Feeder)) 103 is provided above the scanner. The ADF unit 103 automatically conveys the document and sends it to the reading surface of the contact glass.

The operator sets a document on the contact glass above the scanner unit 104 or on the ADF unit 103, selects a mode with the function selection keys on the operation panel 101, confirms the contents displayed on the liquid crystal screen, and presses the numeric keypad, function keys, etc. Operate to set desired image forming conditions. The image forming apparatus is equipped with a call light 100 for indicating the operation status to the operator.

An image signal read by the scanner unit 104 is A/D (Analog/Digital) converted by an SBU (Sensor Board Unit), and then irradiated as laser light from a laser writing unit 112 . The laser beam is condensed by the cylinder lens of the laser writing unit 112 and is line-scanned in the main scanning direction by the polygon mirror to form an electrostatic latent image on the photosensitive drum 116 .

The developing unit 113 includes a cleaning unit 114 and a charging charger around the photosensitive drum 116 . A charging charger 115 is used to charge the photosensitive drum 116 .
A high voltage is applied to the charging charger 115 from a PSU (Power Supply Unit) through a receptacle, an electrode terminal, a conductive bearing, and the like.

The toner supplied from the toner supply unit (toner bottle) 111 as needed and the developer previously filled in the developing unit 113 are agitated and mixed by the internal conveying screw and conveyed to the developing roller. The toner electrostatically attracted by the magnetic force is negatively charged.

The two-component developer carried on the developing roller is regulated in an appropriate amount by developer brush regulating members such as a doctor blade and a casing disposed below the developing roller, and then the triboelectrically charged toner in the two components is biased. The voltage causes it to move onto the photoreceptor drum 116 and selectively adhere to the electrostatic latent image.

The toner density inside the developing unit 113 is detected from the charge amount by a toner density sensor arranged at the bottom position.
Untransferred toner remaining on the photoreceptor drum 116 after transfer is scraped off by a cleaning blade provided in the cleaning unit 114 , transported to a waste toner bottle 125 and collected.

An inlet seal made of Mylar or a sponge-like material is appropriately provided around the developing unit 113 to prevent toner scattering.

A visible image formed by toner on the photosensitive drum 116 is temporarily transferred onto the intermediate transfer belt unit 105 .

The transfer paper conveyed by the paper conveying portion 117 and passed through the registration roller portion passes through the nip between the intermediate transfer belt unit 105 and the secondary transfer unit 118, and is positively charged from the secondary transfer roller to the intermediate transfer belt unit 105. The upper toner is transferred.

Untransferred toner remaining on the intermediate transfer belt unit 105 after the transfer is scraped off by a cleaning blade in the belt cleaning unit 106 and conveyed to and collected in the waste toner bottle 125 .

A high voltage is applied to the transfer roller from the PSU through a receptacle, electrode terminals, conductive bearings, and the like.
In order to suppress fluctuations caused by the printing environment, the type of transfer paper, etc., constant current control is performed, and the transfer current is appropriately switched according to the paper feed tray, transfer paper size, paper thickness, and the like.

In addition, in order to prevent the back side of the transfer paper from being soiled by the toner adhering to the transfer roller, a negative bias is applied to the transfer roller at a predetermined timing to return the adhering toner to the intermediate transfer belt unit 105. be able to. This cleans the transfer roller.

The transfer paper onto which the toner has been transferred is conveyed to a fixing device (fixing unit) 11, where a given temperature and pressure are applied to thermally fuse the toner image onto the paper.
A fixing roller in the fixing device 11 is provided with a thermistor to detect the surface temperature and to perform ON/OFF control of the heater. Thermistors may be contact or non-contact. Also, a thermal fuse is provided to prevent excessive temperature rise.

The fixing device 11 of this embodiment includes a heating means, a fixing member, and a pressure roller that rotates in contact with the fixing member. The fixing member includes, for example, a fixing belt stretched over a fixing roller and a heating roller. The pressure roller forms a nip portion with the fixing belt. Pressurization and depressurization of the nip portion is controlled by a cam. The pressure roller may be provided with heating means (heater) inside.
Other configurations of the fixing device 11 will be described later.

After being separated from the heating roller and the fixing belt by the fixing/separating plate, the transfer paper with the toner image thermally fused is passed through the reversing paper output unit 109, or after double-sided printing is performed according to the setting conditions, and then delivered to the paper output tray. 126 is discharged. When a post-processing device or the like is connected, the paper is conveyed to the transfer paper entrance of the connected device.
The image forming apparatus also includes casters 127 for moving the main body.

The image forming apparatus 10 of the present embodiment performs image formation by electrophotography with the above-described configuration and operation.
Next, the configuration of the fixing device 11 according to the present invention will be described with reference to FIGS. 2 to 4. FIG.
The fixing device of this embodiment includes at least a heating unit (heater), a rotatable fixing member (fixing roller, fixing belt), and a pressure roller that contacts the fixing member to form a nip portion.

As shown in FIG. 2, the fixing device 11 of the present embodiment is mounted on slide rails 12 inside the image forming apparatus 10 so as to be pulled out of the image forming apparatus 10 .
The fixing device 11 includes cover members (an inner cover 30 and an outer cover 31) on the front side in the drawing direction from the image forming apparatus 10 and on the image forming apparatus 10 side.

3 and 4 show the fixing device removed from the image forming apparatus 10. FIG.
As shown in FIG. 4, the fixing device 11 can be divided into an upper separation unit 13 and heating unit 14 and a lower pressure unit 15 .
The pressure unit 15 includes a pressure roller 43 as a pressure member. The heating unit 14 includes a fixing member and heating means (not shown), and the fixing member is composed of a roller member and/or a belt member.

An example of a procedure for maintenance (for example, replacement of components, etc.) of the fixing device 11 will be described.
First, after stopping the printing operation of the image forming apparatus 10 shown in FIG. 2, the fixing device 11 placed on the slide rail 12 is pulled out. At this time, it is preferable to pull out the fixing device 11 after it is sufficiently cooled.
Next, the fixing device 11 is detached from the slide rail 12, left stationary on the work space, and maintenance work is started.
The fixing device 11 can be vertically divided into a separation unit 13, a heating unit 14, and a pressure unit 15, as shown in FIG.

After dividing the fixing device 11 into respective units, necessary maintenance such as part replacement is performed on the target unit.
After the maintenance work is completed, the units are combined, the fixing device 11 is placed on the slide rail 12, and housed in the image forming apparatus 10. FIG.

In the fixing device of this embodiment, the pressure roller 43 has bracket members at both ends in the rotation axis direction.
FIG. 5A is a perspective view schematically showing bracket members 50 at both ends of the pressure roller 43, and FIGS. 5B and 5C are side views.
The bracket member 50 (50a, 50b) includes a rotating shaft portion support surface 52 (52a, 52b) through which the rotating shaft portion 46 is inserted, and an outer periphery of a bearing member (ball bearing) 42 that rotatably supports the rotating shaft portion 34. and bearing member support surfaces 51 (51a, 51b) facing each other.
The pressure roller 43 has a drive gear 41 at one end, a heater (not shown) inside, and a heater harness 40 extending from both ends.

In FIG. 5A, an arrow D1 indicates the direction in which the recording medium (paper) P is conveyed, an arrow D2 indicates the side of the main body of the image forming apparatus, and an arrow D3 indicates the front side in the drawing direction.
In the following description, the one end side (arrow D2 side) provided with the drive gear 41 is sometimes referred to as the "driving side", and the other end side (arrow D3 side), which is the front side in the drawing direction, is referred to as the "operating side". Sometimes.

In the fixing device of this embodiment, the bearing member support surfaces 51 (51a, 51b) of the bracket members 50 (50a, 50b) have knob portions 60 (60a, 60b) that can be gripped with fingers.
Both of the knob portions 60 ( 60 a and 60 b ) are arranged on the upstream side in the conveying direction D<b>1 of the recording medium P with respect to the rotating shaft of the pressure roller 43 .
With such an arrangement, an appropriate balance can be obtained with respect to the center of gravity of the entire pressure unit 15 including the pressure roller 43 when the grip portion 60 is gripped and lifted.

Further, the arrangement position of the knob portion 60a in the bracket member 50a on one end side (driving side) of the pressure roller 43 is different from the arrangement position of the knob portion 60b in the bracket member 50b on the other end side (operating side). preferably.
For example, as shown in FIG. 5A, a bracket member 50a on one end side (driving side) of the pressure roller 43 has a knob portion 60a extending in the direction of the rotation axis of the pressure roller 43. The bracket member 50 b on the other end side (operating side) may be arranged such that the knob portion 60 b extends in a direction perpendicular to the rotation axis of the pressure roller 43 .

The arrangement positions of the knob portions 60 (60a, 60b) are different on the drive side and the operation side, and are asymmetrical, so that it is easy to balance with respect to the center of gravity of the pressure unit 15 and the pressure roller 43, and lift and move. Easier to apply force and improve handling when moving, leading to improved workability.

Furthermore, as shown in FIG. 5, the knob 60 (60a, 60b) preferably has openings 61 (61a, 61b) where fingers can be put when gripping.
When gripping the knobs 60 (60a, 60b) with fingers, the operator's fingers are caught on the openings 61 (61a, 61b), thereby providing a non-slip effect and ensuring secure gripping.

Next, the form of the grip portion 60 (60a, 60b) will be described. The knob portion 60 (60a, 60b) is arranged at a predetermined angle with respect to the bearing member support surface 51 (51a, 51b).
As shown in FIGS. 6(A) and 6(B), the bracket member 50a on the one end side (driving side) of the pressure roller 43 has the knob portion 60a at an angle of 90° to 135° to the bearing member supporting surface 51a. The bracket member 50b on the other end side (operating side) is arranged at an angle of 100°, and as shown in FIGS. It is preferably arranged at an angle of between ° and 90°.

Further, the knob portions 60 (60a, 60b) of the bracket members 50 (50a, 50b) have raised portions substantially perpendicular to the bearing member support surfaces 51 (51a, 51b) and inclined surfaces bent from the raised portions. The inclined surface of the knob portion 60a of the bracket member 50a on the one end side (driving side) of the pressure roller 43 is 90° to 135° with respect to the bearing member supporting surface 51a as shown in FIG. 6(C). , and the inclined surface of the knob portion 60b of the bracket member 50b on the other end side (operating side) is at an angle of 45° to 90° with respect to the bearing member support surface as shown in FIG. 7(C). is preferred.

As shown in FIGS. 6(D) and 7(D), the knobs 60 (60a, 60b) have openings 61 (61a, 61b) on which fingers can be put when gripping. there is

With such a configuration, the grip portion 60 (60a, 60b) can be easily and reliably gripped, and the operability and handleability of the pressure roller 43 are improved.
In particular, in the embodiment shown in FIGS. 6(C) and 7(C) having an inclined surface bent from the rising portion, the opening 61 (61a, 61a, 61b) is preferably formed.

As described above, the pressure roller 43 and/or the pressure unit 15 lifted by gripping the knobs 60 (60a, 60b) are moved and temporarily placed in a work space or the like. At this time, it is required that the surface of the pressure roller 43 does not come into contact with the installation surface and that it does not fall down in the installed state.

On the other hand, in the fixing device of this embodiment, as shown in FIGS. The length from the bearing member support surface 51 (51a, 51b) side to the end on the opposite side is longer than the diameter of the pressure roller 43, and the end on the side opposite to the bearing member support surface 51 (51a, 51b) is , leg portions 70 (70a, 70b) that come into contact with the installation surface when the pressure roller 43 is removed.

The legs 70 (70a, 70b) are parts that come into contact with the installation surface, and have a shape projecting in the X direction in the drawings, as shown in FIGS. 5B and 5C, for example. The shape is not limited to this, and any shape can be used as long as stability can be obtained at the time of installation, and the length in the XY direction and the contact area can be appropriately adjusted.

By configuring the rotary shaft support surfaces 52 (52a, 52b) as described above, the risk of damage when the pressure roller 43 is removed can be reduced.
The detached pressure roller 43 can be installed in the work space, and necessary maintenance and parts replacement (for example, heater member replacement) can be performed.

As described above, according to the fixing device of the present embodiment, the operability of movement when attaching and detaching the pressure roller 43 and the pressure unit 15, and the stability when temporarily placed is improved. Regardless of the environment and working conditions, it is possible to improve the workability of maintenance and part replacement of the pressure unit 15 having the pressure roller 43 .

10 image forming apparatus 11 fixing device (fixing unit)
12 slide rail 13 separation unit 14 heating unit 15 pressure unit 30 cover member (inner cover)
31 cover member (exterior cover)
40 heater harness 41 drive gear 42 bearing member (ball bearing)
43 Pressure roller 46 Rotating shaft 50 Bracket member 51 Rotating shaft support surface 52 Bearing member support surface 53 Rotating shaft support 60 Knob D1 Paper transport direction D2 Image forming apparatus main body side D3 Drawer direction front side

Japanese Patent Application Laid-Open No. 2004-039502

Claims (7)

At least a heating means, a rotatable fixing member, and a pressure roller contacting the fixing member to form a nip portion,
The pressure roller has bracket members at both ends in the rotation axis direction,
The bracket member is
a rotating shaft support surface through which the rotating shaft is inserted;
a bearing member supporting surface facing an outer peripheral surface of a bearing member provided above the rotating shaft portion supporting surface and rotatably supporting the rotating shaft portion;
The rotating shaft portion supporting surface is a leg portion whose end on the side facing the bearing member supporting surface side is in contact with the installation surface,
The rotating shaft portion is inserted through the rotating shaft portion support surface via the bearing member,
The bearing member support surface has a grip portion that can be gripped with fingers, and the grip portion is arranged on the upstream side in the conveying direction of the recording medium with respect to the rotation shaft of the pressure roller. and fixing device. 2. The fixing device according to claim 1, wherein a position of the knob portion on the bracket member on one end side of the pressure roller is different from a position of the knob portion on the bracket member on the other end side of the pressure roller. Device. The bracket member on one end side of the pressure roller is arranged so that the knob portion extends in the direction of the rotation axis of the pressure roller, and the bracket member on the other end side is arranged such that the knob portion is attached to the pressure roller. 3. The fixing device according to claim 1, wherein the fixing device is arranged to extend in a direction perpendicular to the rotation axis. In the bracket member on one end side of the pressure roller, the knob portion is disposed at an angle of 90° to 135° with respect to the bearing member support surface, and in the bracket member on the other end side, the knob portion is the bearing member. 4. The fixing device according to claim 1, wherein the fixing device is arranged at an angle of 45° to 90° with respect to the supporting surface. the knob portion of the bracket member has a rising portion substantially perpendicular to the bearing member supporting surface and an inclined surface bent from the rising portion;
The inclined surface of the knob portion of the bracket member on one end side of the pressure roller has an angle of 90° to 135° with respect to the bearing member supporting surface, and the inclined surface of the knob portion of the bracket member on the other end side of the pressure roller. is an angle of 45° to 90° with respect to the bearing member supporting surface. 6. The fixing device according to claim 1, wherein the grip portion has an opening through which a finger can be put when gripping. An image forming apparatus comprising the fixing device according to claim 1 .

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